Though there are many myths that detail the events leading to the creation of the Olympics, based on the records, the first Olympic Games were held in 776 B.C. in Southern Greece. Interestingly, the common idea among the origin myths is that the games were intended to thank the gods for a particular victory.
The Olympics were of such importance to the ancient Greeks that they used that first Olympiad and the four years between games as the basis of their dating system. These ancient games lasted over 1,000 years until Roman Emperor Theodosius I ended them in 391 A.D.